The term “genset” is generally understood as at least one arrangement of a generator driven by a drive device for generating electrical energy.
To do so, a mechanical power of the drive device, if necessary via a transmission unit, is input into the at least one generator, which in turn converts it into electrical power. This electrical power is hereinafter delivered to the power grid.
During a grid fault in a power grid, in particular during an electrical short circuit in at least one phase of the power grid, and the associated drop in grid voltage and increase of grid current in the power grid, unwanted changes of generator operating variables can occur in a generator, in particular in a synchronous generator, such as the rotational speed or the pole wheel displacement angle or load angle, because the drop of the grid voltage causes a significant reduction of the electrical power output from the generator to the power grid. In the case of conventional configurations in which a rotor of the generator is connected to a shaft of a drive device (for example, an internal combustion engine) which drives the rotor, this electrical power drop can cause a corresponding increase in the rotational speed of the drive device and thus of the rotor. As a result, the synchronization of the generator with the power grid can be lost or even a damage in the generator can be caused.
The so-called load angle is the angle at which the pole wheel of a synchronous machine rotates ahead (generator operation) or behind (motor operation) the synchronous rotary field.
The conventional approach to react to such grid faults is to take appropriate measures to counteract such an increase of the rotational speed and an associated increase in the load angle of the generator. Thus, measures are usually taken which reduce the rotational speed and the load angle. Such an exemplary measure is the reduction of the acceleration torque by correspondingly throttling a drive device connected to the generator.
Such methods for regulating a drive device are already known, for example, from AT 514 811 A1 and WO 2010/134994 A1. In the presence of a grid fault, an internal combustion engine (which functions as a drive device) is regulated here via the fuel supply or the ignition unit.
However, it has been shown that the conventional measures for a grid fault in certain situations are still associated with a greater change in the load angle.